Syringes are known for storing and transporting substances with fluid properties such as gases, liquids, pastes, slurries, and the like. A syringe may include a barrel defining a bore in communication with a port, and a piston disposed within the barrel. Translation of the piston away from the port may draw material into the barrel through the port. Alternatively, translation of the piston toward the bore may expel material from the barrel out of the port.
A syringe barrel may be formed from a transparent or translucent material, such that a position of the piston within the bore is visible through the barrel. Further, the syringe barrel may include indicia disposed thereon, such that longitudinal alignment of the piston relative to the indicia may visually indicate a volume of material stored between the piston and the port.
U.S. Pat. No. 5,009,645 (hereinafter, “the '645 patent”) purports to describe a syringe for dispensing measured quantities of a material (e.g., a medicament). The syringe from the '645 patent includes a barrel, a plunger rod having a cruciform transverse cross section, and an infinitely adjustable stop member secured to the plunger rod for positively setting the length of travel of the plunger rod to thereby control the volume of material dispensed from the syringe. However, sequential delivery of multiple doses using the syringe from the '645 patent may be subject to dosage errors resulting from inaccurate displacement of the infinitely adjustable stop member between dose deliveries, undue time consumption to adjust the position of the infinitely adjustable stop member, or both.
U.S. Pat. No. 5,601,077 (hereinafter, “the '077 patent”) purports to describe a syringe with a dose limiting housing for preventing delivery of a predetermined amount of liquid from the syringe by limiting a travel of a plunger within a barrel of the syringe. The '077 patent states that the dose limiting housing is adapted to interact between a radially extending projection on the plunger rod, such as a flange, and a proximal end of the syringe barrel, which includes a barrel flange, to limit the distal motion of the plunger rod with respect to the barrel. However, the dose limiting housing of the '077 patent may effect delineation of no more than two distinct ranges of plunger travel, corresponding to the housing installed on the syringe and the housing removed from the syringe, because the dose limiting housing has only two axial bearing surfaces.
U.S. Pat. No. 5,951,526 (hereinafter, “the '526 patent”) purports to describe a nasal syringe in which the travel of the plunger is controlled by a stop mechanism. The syringe of the '526 patent includes a stop coupled to an end cap by a hinge. However, the stop mechanism of the '526 patent may effect delineation of no more than two distinct ranges of plunger travel corresponding to an interfering position and a non-interfering position of the stop mechanism about the hinge.
U.S. Patent Publication No. 2005/0137532 (hereinafter, “the '532 publication”) purports to describe a unit to administer medication having a plunger with non-reusable stroke stops sequentially arranged along the plunger. According to the '193 patent, the stroke stops are frangible about a weakening line, such that each broken stroke stop enables the forward movement of the impelling plunger and the administration of a corresponding dose. However, the stroke stops of the '532 publication may interfere with filling an empty syringe so configured, and therefore limit application to pre-filled syringes. Further, the stroke stops of the '532 patent are inherently non-reusable because of their frangible nature, and the stroke stops may be complex and expensive to manufacture.
U.S. Pat. No. 5,318,544 (hereinafter “the '544 patent”) purports to describe a syringe for metering predetermined volumes of fluid therefrom. The syringe of the '544 patent includes a tube, a clip, and a metering plunger having stop surfaces disposed thereon, where the plunger is inserted through an opening in the clip and is slidably located within the syringe tube. However, the plunger stop surfaces of the '544 patent have complex shapes and could be difficult or expensive to manufacture. Further, the stop surfaces of the '544 patent may interfere with filling an empty syringe by requiring rotation of the plunger in addition to axial translation during a ruling step.
U.S. Patent Publication No. 2003/0004467 (hereinafter “the '467 publication”) purports to describe a multi-dose syringe allowing sequential injection of identical or non-identical volumes. A plurality of stops are arranged at various axial and azimuthal locations about a plunger shaft of the '467 publication, such that the stops may axially interfere with or pass through a screw knob disposed depending on azimuthal alignment of the plunger shaft with the screw knob. However, the plunger stops of the '467 publication have complex shapes that may be difficult or expensive to manufacture. Further, the plunger stops of the '467 publication may interfere with filling an empty syringe by requiring rotation of the plunger in addition to axial translation during a filling step.
Accordingly, there is a need for an improved syringe that enables accurate delineation of more than two ranges of plunger translation relative to a barrel, that facilitates filling of an empty syringe so configured, and that s simple and inexpensive to manufacture.